Hydraulic chamber incorporating a jet nozzle

ABSTRACT

A hydraulic chamber incorporating a nozzle capable of delivering a very high instantaneous pulsed dynamic jet in apparatus producing a shock wave in a relatively incompressible liquid is obtained when the effective locus of the shock wave is such that the pressure wave generated thereby is transmitted to build up rapidly and uniformly in a direction along the centerline of the nozzle. A suitable configuration for such chamber is a parabolic cissoid in which the locus of the shock wave is effectively at the focal point of the parabolic portion of such chamber thereby converting the resultant spherical waves into additive plane waves in the direction of the centerline of the nozzle opening. The shock wave employed in the apparatus can be produced by mechanical or electrical energy, or a combination thereof.

0 United States Patent [151 3,647,137 Naydan 5] Mar. 7, 1972 [54]HYDRAULIC CHAMBER 3,447,322 6/1969 Mastrup ..60/203 INCORPORATING A JETNOZZLE 3,452,565 7/1969 Cadwell... ..72/56 3,521,820 7/ I970 Cooley..239/60l X [72] Inventor: Theodore T. Naydan, Schenectady, N.Y. [73]Assignee: Environment/One Corporation, Schenecf f' Knowles tady,Assistant Examiner-Edwin D. Grant Attorney-Charles W. Helzer and AlbertC. Hodgson [22] Filed: Oct. 20, 1970 Y 211 App]. No.: 82,320 [57]ABSTRACT A hydraulic chamber incorporating a nozzle capable of 52 us. Cl239/102 60/203 60/221 delivem'g a high insamamus Pulsed dynamicje239/60l paratus producing a shock wave in a relatively incompressible 51Int. Cl B050 7/30 liquid is mined when have shmk wave is [58] Fieldorsemhnuuuunuli 239E115 1 62 601 101- such pressu'e wave genemed them isammited 6 5 1 to build up rapidly and uniformly in a direction along thecenterline of the nozzle. A suitable configuration for such chamber is aparabolic cissoid in which the locus of the shock [56] References Citedwave is effectively at the focal point of the parabolic portion UNITEDSTATES PATENTS of such chamber thereby converting the resultantspherical waves into additive plane waves in the direction of thecenter- 3913384 12/1961 Smlth line of the nozzle opening. The shock waveemployed in the $141,296 7/1964 Jacobs at apparatus can be produced bymechanical or electrical ener- 3,325,858 6/1967 Ogden et al.. gy or acombination th f 3,350,885 11/1967 Hall et a]. 3,426,545 2/1969 Lloyd..60/203 X 5 Claims, 4 Drawing Figures PATENTED 7 SHEET 1 [IF 2INVENTOII THEODORE T. NAYDAN ATTOR N BY PAIENTEUMAR 71912 3. 647. 137

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0|23456789X" NOZZLE LENGTH-INCHES FIG. 3

ENERGY CONTENT OF VARIOUS NOZZLE SHAPES E 50 LL] 5 40 8 g so I M4MMWCISSOIDL '0 H W V -A u V OJ .2 5.4.5.6789

NOZZLE LENGTH-INCHES mvnn'ron THEODORE T NAYDAN av aw/69 AT'I'OR N EYHYDRAULIC CHAMBER INCORPORATING A JET NOZZLE BACKGROUND OF THE INVENTIONl. Scope of the Invention This invention relates to a shaped hydraulicchamber incorporating a nozzle and capable of delivering a very highinstantaneous pulsed dynamic liquid jet in apparatus employing thedischarge of electrical energy within liquid contained in such a chamberto create a shock wave which powers the jet.

' 2. The Prior Art It is well known that a liquid jet having asufficiently high velocity can be used to fracture, cut, form ordisintegrate various materials. The creation of such jets has beenproposed by such diverse methods as the use of centrifugal force and theforce transferred to confined liquid by a freely accelerating body.Attempts have also been made to employ the principle of acceleration ofthe foremost portion of liquid travelling within a contracting cavity.

My copending application Ser. No. 83,218 filed Oct. 20, 1970, now US.Pat. No. 3,592,866 and entitled Process and Apparatus for the Productionof Hydroelectric Pulsed Liquid Jets, the disclosure of which isincorporated herein by reference is directed to the production ofhigh-energy liquid jets by the discharge of electrical energy through arelatively incompressible liquid in an essentially closed chamber havinga shaped outlet nozzle. This application discloses that the discharge ofelectrical energy from a suitable source such as a capacitor bank into aclosed container of a suitable liquid such as water by means of propercoupling electrodes will generate a high-temperature channel between theelectrodes. Since the delivery of the electrical energy to the spark gapbetween the electrodes is at a faster rate than the ability of theliquid to absorb the heat generated thereby, a rapidly expanding gaseousbubble is formed in the channel between the electrodes. The rapidexpansion of the gaseous bubble produces a shock wave in the relativelyincompressible fluid. This shock wave meets mechanical resistance at alldirections except through the nozzle opening. Thus the shock wave actsto force a jet of liquid through the nozzle opening.

The prior art has disclosed both conical and exponential configurationsfor jet nozzles for delivering high-velocity liquid jets. Because ofsuch factors as turbulence, back pressure and the like, suchconfigurations have been inefficient and have produced relatively slowand nonuniform pressure buildup. The exponential configuration has shownimproved characteristics over the conical configuration.

SUMMARY OF THE INVENTION In accordance with the present invention, ithas been discovered that the shape of the hydraulic reaction chamberincluding the shape of the jet forming nozzle has a marked effect on theforce of the resultant jet.

It is an object of the present invention to provide an improvedhydraulic chamber and jet nozzle for the production of high-pressureliquid jets.

It is a further object of the present invention to provide an improvedhydraulic chamber and jet nozzle which will more effectively utilize theshock wave produced within such chamber to drive a jet of liquid throughthe jet nozzle.

According to the present invention these objects are achieved by shapingthe internal cavity of the hydraulic chamber so that the pressure waveformed therein is a plane wave and shaping the jet nozzle portion of thehydraulic chamber so that the pressure therein resulting from the planepressure waves builds up uniformly and gradually to its final peak valueat the outlet end of the jet nozzle.

In my copending application Ser. No. 83,218, entitled Process andApparatus for the Production of Hydroelectric Pulsed Liquid Jets" thereis described in detail the circuitry and apparatus required to producehigh-energy pulsed liquid jets by the discharge of electrical energyinto a liquid contained in a suitable hydraulic chamber. Reference ismade to this application for complete details of the severalembodimentsand the disclosure thereof is incorporated herein by suchreference. Generally this application discloses that the discharge ofstoredelectrical energy from a suitable source into a relativelyincompressible liquid such as water contained in a hydraulic chamberhaving a single outlet nozzle by means of proper coupling electrodeswill result in the production of a rapidly expanding gaseous bubble inthe channel between the electrodes. Since expansion of the bubble takesplace during the relatively short time period of energy release a shockwave is produced in the liquid within the chamber. Since the hydraulicchamber is essentially a closed container except for the jet nozzleopening, this shock wave meeting mechanical resistance in all directionsexcept through the nozzle opening will drive a slug or jet of liquidthrough the opening at a high velocity.

The shock wave thus produced by the rapidly expanding gaseous bubbleradiates spherically within the hydraulic chamber from the point offormation between the electrodes. It has now been discovered inaccordance with the present invention that this spherically radiatingshock wave can be converted into a plane wave with its effective locusat the point of discharge and with the direction of propagation in thedirection of the jet nozzle opening if that portion of the hydraulicchamber opposed to the jet nozzle opening has a parabolic configuration.If the configuration of such a chamber is so selected and the focus ofthe parabolic configuration is at the point of formation of thespherical shock wave between the electrodes, then that portion of thespherical shock wave radiating in the direction of the parabolicconfiguration will be converted into a plane wave with its direction ofpropagation in the direction of the jet nozzle opening.

It has further been discovered in accordance with the present inventionthat the shape of the jet nozzle has a marked effect on the buildup ofpressure in the nozzle and on the momentum imparted to the liquid jetdelivered by the nozzle. In order to maximize the momentum and hence thekinetic energy imparted to the liquid jet, it is necessary to build upthe velocity in the converging jet nozzle both uniformly and rapidly. Ithas now been discovered that such unifonn and rapid velocity buildup canbe achieved in a convergingjet nozzle having the shape of a cissoid ofDiocles as a surface of revolution about the centerline of the nozzle inaccordance with the cissoid equation:

Where: r is the internal radius of the nozzle along the length l l isthe length along the nozzle 2a is the entrance radius of the nozzle Itmay readily be seen that while each of these features contributessubstantially to improved performance of a liquid jet apparatus, thecombination of features results in a jet with an output far markedlyexceeding heretofore known apparatus for comparable input of energy.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of oneembodiment of an electrohydraulic jet apparatus according to the presentinvention;

FIG. 2 is a cross-sectional view of a second embodiment of anelectrohydraulic jet apparatus according to the present invention;

FIG. 3 is a graph of the velocity buildup in a jet nozzle ex pressed asa function of nozzle length; and

FIG. 4 is a graph of the energy content of liquid in a jet nozzleexpressed as a function of nozzle length.

' DESCRIPTION OF PREFERRED EMBODIMENTS The improved hydraulic chamber ofthe present invention can best be described with reference to thedrawings. For purposes of illustration a single electrohydraulic jetapparatus is shown.

In the embodiment shown in FIG. 1 the electrohydraulic apparatusincludes a hydraulic chamber 11 having a jet nozzle opening 12. Liquidis supplied to the chamber 11 under pressure from a source (not shown)through line 13 to a supply port 14 opening into the chamber 11 atanysuitable location. Electrodes 15, 16 are positioned within the chamber11. The hydraulic chamber 11 includes a parabolic portion 17. Theelectrodes 15, 16 are so arranged within the chamber 11 that thedischarge channel 18 between the electrodes 15, 16 coincides with thefocus of the parabolic portion 17 of the hydraulic chamber 11. Thehydraulic chamber 11 has a second portion 19 which is the nozzle portionand terminates in the jet nozzle opening 12. The nozzle portion 19 hasthe configuration of a cissoid of Diocles.

The electrodes 15, 16 are insulated from the hydraulic chamber 11 byinsulating means 20 and preferably are provided with sleeves 21, 22. Thesleeves 21, 22 are insulated from the electrodes 15, 16 and thehydraulic chamber 11 by the insulating means 20. The jet nozzle opening12 is selectively closed by means of a valve or shutter 23. In a furthermodification, the valve or shutter can be dispensed with and the chamber11 filled with water on a continuing basis which develops an aiming ordirective stream out the nozzle when not electrically energized and apulsed stream when energized. A spring-loaded, unidirectional ball valveplaced in line 13 permits water to enter chamber 11 in one direction butnot in the reverse direction when electrodes l5, 16 are energized. Theelectrodes 15, 16 are connected through switch means 24 to a source ofelectrical energy. This is represented in a capacitance 25 charged by ahigh-voltage source (not shown) but can be any suitable source such asan induction coil, transformer or the like. The shutter 23 is connectedthrough sensor means 26 to the switch means 24 to cause the shutter 23to open the nozzle opening 12 in timed relationship to the discharge ofelectrical energy. When the switch means 24 is actuated, the electricalenergy in the capacitance 25 is discharged across the discharge channel18 between the electrodes l5, 16. The hydraulic chamber 1 1 is filledwith liquid at the time of discharge. A gaseous bubble will be formed inthe liquid in the discharge channel 12. The high temperature andpressure developed in the channel 18 by the discharge of electricalenergy therein will cause the bubble to expand at a rapid rate creatinga spherical shock wave radiating outward from the point of discharge.The point of discharge 18 is at the focus of the parabolic portion 17 ofthe hydraulic chamber 11 and on a line with the jet nozzle opening 12.The spherical shock wave radiating in the direction of the parabolicportion 17 of the chamber will be reflected back to the focus 18 of thatportion of the chamber being thereby converted into a plane shock wavewhich has its direction of propagation in the direction of the jetnozzle opening 12. The effective locus of this shock wave is the pointof discharge 18. This will reinforce the effect of the remainder of theshock wave. This reinforced shock wave drives the liquid in the nozzleportion 19 of the hydraulic chamber 11 in the direction of the jetnozzle opening 12. Since the configuration of the nozzle portion 19 ofthe hydraulic chamber 11 is that of a cissoid of Diocles, the pressurebuildup within the nozzle portion 19 will be rapid and uniform. Theliquid will exit from the nozzle opening 12 with a high momentum.

In the embodiment of FIG. 2, the operation is similar to that of theembodiment of FIG. 1. A freely accelerating piston 30 is employed tocompress the liquid in the hydraulic chamber 11 prior to the dischargeof the capacitance 25 between the electrodes l5, 16. The liquid issupplied to the piston cylinder 31 through suitable means such as a port32. The piston 30 is driven at a high rate of speed through the cylinder31 by external power means (not shown). The piston picks up the liquidsupplied by the port 32 and accelerates this liquid during delivery tothe hydraulic chamber 11. The liquid thus enters the hydraulic chamber 11 at a high rate of speed and with considerable force. It fillsthereaction chamber and at the instant that the chamber 11 is filled, andpiston 30 is attop dead center position, switch means 24 causes adischarge of the electrical energy in the discharge channel 18. The face33 of the piston 30 is designed to conform to and form a continuationwith the parabolic portion 17 of the hydraulic chamber 11.

FIGS. 3 and 4 show graphically the improved result obtained by thecissoid nozzle configuration 19 of the present invention. The cissoid ofDiocles nozzle configuration 19 is compared with an exponentialconfiguration 29 and a conical configuration 39. All other factorsexcept configuration were the same. The nozzle length in each instancewas 1 inch, the:

entrance diameter was 0.7 inch and the exit diameter was 0.08

inch. I

FIG. 3 illustrates the superior uniform and rapid velocity buildupaccomplished with the cissoid nozzle configuration. Velocity developedat 60 percent of nozzle length by the cissoid nozzle is 6 times that ofthe conical nozzle 39, and 1.8 times that of the exponential nozzle 99.

FIG. 4 illustrates the superior property of the cissoid nozzleconfiguration 19 of the present invention as compared with anexponential nozzle configuration 29 and a conical configuration 39.Again all factors except nozzle configuration were the same. Energycontent of the liquid rises more rapidly with the cissoid nozzleconfiguration and is higher at any given point along the nozzle lengthfor the cissoid configuration 19 over the exponential configuration 29and the conical configuration 39. It can thus be seen that the cissoidconfiguration is much more efiicient than the exponential or conicalconfiguration in generating the requisite high-pressure liquid jets.

Although the present invention has been described in connection with thepreferred embodiments, it is to be understood that modifications andvariationsmay be resorted to without departing from the spirit and scopeof the-invention, as those skilled in the art will readily understand.For example, the shock wave utilized to impart momentum to the water jetcan be produced by any suitable mechanical, electrical, chemical orhydraulic means, or any combination thereof capable of producing such ashock wave in a relatively incompressible liquid confined in a hydraulicchamber with the configuration or configurations disclosed herein. Suchmodifications and variations are considered to be within the purview andscope of the invention and the appended claims.

I claim:

1. In a hydraulic chamber for obtaining high pulse dynamic liquidpressure jets from a shock wave generated in a substantiallyincompressible liquid contained therein for discharge through a nozzleforming a part thereof, the improvement wherein the effectiveconfiguration of said chamber at the instant of production of the shockwave is that of a parabolic cissoid.

2. In the hydraulic chamber of claim 1, wherein the port of the chamberforming the nozzle has the cissoid configuration.

3. A jet nozzle for obtaining high pulse dynamic liquid pressure jetsfrom a shock wave generated in a substantially incompressible liquidadjacent the entrance of said nozzle, said nozzle having theconfiguration of a cissoid of Diocles.

4. A jet nozzle for the production of hydraulic liquid jets having aninternal configuration corresponding to a surface of revolution aboutthe centerline of said nozzle of a cissoid of Diocles.

5. A hydraulic chamber for the production of high-pressure liquid jetspowered by a shock wave generated at a point therein by the discharge ofelectrical energy in an incompressible liquid confined in said chamberwherein the chamber has a first portion having a parabolic configurationand a second portion having a nozzle opening therein and a configurationconforming to a surface .of revolution of a cissoid about the centerlineof said opening, the point of generation of the shock wave being thefocus of the parabolic configuration of said first portion and adjacentthe intersection of said first and second portions and on the centerlineof the nozzle opening of said second portion.

UNITED STATES ATENT OFFICE CERTIFICATE OF CORRECTION 3, 47,137 DatedMarch 7," 1972 Patent No.

Theodore T. Naydan Inventor(s) It is certified that error appears in theabove-identified patent and that said Letters Patentare hereby correctedas shown below:

line 22, "now U.S. Patent No. 3,592,866" should be cancelled; line 70,"83,218" should read 83,219

Signed and sealed this 24th day of October 1972.

' (SEAL) Attest:

EDWARD M.FLE1CHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents U. 5. GOVERNMENT PRINTING OFFICE: I989 0-365-334.

F ORM PO-IOSO (10-69)

1. In a hydraulic chamber for obtaining high pulse dynamic liquidpressure jets from a shock wave generated in a substantiallyincompressible liquid contained therein for discharge through a nozzleforming a part thereof, the improvement wherein the effectiveconfiguration of said chamber at the instant of production of the shockwave is that of a parabolic cissoid.
 2. In the hydraulic chamber ofclaim 1, wherein the port of the chamber forming the nozzle has thecissoid configuration.
 3. A jet nozzle for obtaining high pulse dynamicliquid pressure jets from a shock wave generated in a substantiallyincompressible liquid adjacent the entrance of said nozzle, said nozzlehaving the configuration of a cissoid of Diocles.
 4. A jet nozzle forthe production of hydraulic liquid jets having an internal configurationcorresponding to a surface of revolution about the centerline of saidnozzle of a cissoid of Diocles.
 5. A hydraulic chamber for theproduction of high-pressure liquid jets powered by a shock wavegenerated at a point therein by the discharge of electrical energy in anincompressible liquid confined in said chamber wherein the chamber has afirst portion having a parabolic configuration and a second portionhaving a nozzle opening therein and a configuration conforming to asurface of revolution of a cissoid about the centerline of said opening,the point of generation of the shock wave being the focus of theparabolic configuration of said first portion and adjacent theintersection of said first and second portions and on the centerline ofthe nozzle opening of said second portion.